This invention relates to an improved process for the addition reaction of halogenated hydrocarbon olefins with perfluoroalkyl iodides.
The present invention may be considered to be in a related area of technology as prior art patents, namely, Blanchard et al., U.S. Pat. No. 3,226,449, and Brace U.S. Pat. No. 3,145,222.
Blanchard et al., U.S. Pat. No. 3,226,449, employ starting materials of specific perfluoroalkyl iodides with tetrafluorethylene to obtain higher perfluoroalkyl iodides in the presence of a free radical generating catalyst.
The process of Blanchard et al teaches injecting during a reaction cycle tetrafluoroethylene and a free radical generating catalyst into liquid perfluoroethyl iodide and mixtures thereof with n-perfluorobutyl iodide. The liquid charge also contains the catalyst in a vessel maintained at a pressure between 225 psi to 700 psi at a temperature of 80.degree. to 170.degree.C. The reaction mixture products are of the structure F(CF.sub.2).sub.m I wherein m is an even integer from 6 to 12.
The process disclosed by Blanchard et al represents a contribution to the art; however, several inherent limitations exist, namely:
1. Process is limited to a narrow range of source materials. PA1 2. Process is limited to relatively high pressure conditions involving expensive equipment and hazardous reaction conditions. PA1 3. Process is limited to production of telomers.
Brace, U.S. Pat. No. 3,145,222 discloses perfluoroalkyl iodides can be added to olefins in the presence of free radical generating catalysts in acceptable conversions and yields. The process disclosed by Brace in U.S. Pat. No. 3,145,222 is carried out at temperatures ranging from about 50.degree. to about 190.degree.C, depending primarily upon the specific free radical generating catalyst that is employed. If the olefin employed is a gas at reaction temperature and atmospheric pressure, then a super-atmospheric pressure system must be employed in the practice of the Brace process. This naturally adversely affects the economic feasibility of the process because of the expensive pressure equipment necessary to maintain the conditions and the complication involved thereby. Thus, for example, in order to adjust the concentration of the reactants, the pressure must be adjusted. Safety in operation is also sacrificed by the necessity of working with flammable gas under pressure.
In contrast to known technology, the present process represents important advantages of the teachings of the prior art as exemplified by the Blanchard et al. and Brace disclosures.
It is an object of the present invention to produce a reactant addition product of perfluoroalkyl iodides and gaseous halogenated olefins which product is formed at or below atmospheric pressure.